Experimental and numerical studies of a fatty acid based phase change dispersion for enhancing cooling of high voltage electrical devices

A fatty acid based phase change dispersion (PCD) for efficient high voltage electrical devices cooling has been developed and investigated in this paper. Experiments were firstly conducted to characterise the PCD thermophysical properties and to measure the bulk fluid and inner wall temperature of PCD flowing in a circular pipe by a self-designed rig. A 3D modelling based on the Euler-Euler model and homogenous single-phase model were then performed and validated through experiments, and further employed to evaluate the effects of particle size, concentration and operating conditions on flow characteristics, pressure drop, heat transfer and energy transport performance of the PCD. The results showed that both the particle size and concentration presented significant influences on heat transfer between the two phases, and average friction factor as well as heat transfer coefficient of the PCD. A higher averaged Nusselt number and a larger pressure drop were observed when the PCM particle diameter decreased to 7 mm. For the investigated conditions in this work, an optimal set of cooling performance for the developed fatty acid PCD was proposed and a PCM particle size of 7 mm under a flow velocity of 4 m/s and a concentration of 35% was recommended for industrial cooling applications. (C) 2020 Elsevier Ltd. All rights reserved.